Effects of ferulic acid on the airway hyperresponsiveness and airway inflammation. (a) Oral administration of FA suppressed the development of AHR in OVA-sensitized mice. One day after the last OVA challenge, airway resistance was measured in response to increasing concentrations of methacholine (0~32 mg/mL) by invasive body plethysmography. Results are expressed as the mean ± SEM (n = 8 in each group) of the pulmonary resistance (R
L) after PBS nebulization. (b) Changes in the cellular composition of the BALF of mice exposed to an aerosolized allergen. One day after measuring the pulmonary function parameters, each group of mice was sacrificed, and the BALF was collected. Cells were counted and classified as macrophages (Macro), eosinophils (Eos), neutrophils (Neu), and lymphocytes (Lym). Results are expressed as the mean ± SEM (n = 8 in each group). (c) Effect of FA on lung inflammatory cell infiltration in OVA-induced allergic asthmatic mice (H&E staining). Lung sections were obtained from NC mice, sterilized water-treated PC mice, and those treated with different doses of FA. Sections were stained with H&E for the morphological analysis. Tissues were examined by light microscopy (original magnification: ×200). ∗
p < 0.05, ∗∗
p < 0.01, and ∗∗∗
p < 0.001 versus the PC group.